1. Field of the Invention
The invention relates to an apparatus for mixing reaction resin compounds and for keeping the pressure of the said reaction resin compounds constant.
2. Description of the Prior Art
Reaction resin compounds are manufactured by mixing precisely prescribed quantities of resin and hardener, whereby a plurality of resins and a plurality of hardeners are used in many cases. Morever, additional substances such as fillers, dyestuffs, adhesion promoters, accelerators and the like can also be distributed into the resin and the hardener components. In the automatic production of such reaction resin compounds from, for example, one resin and one hardener component by means of oscillating or rotating displacement pumps and static or dynamic flow-through mixers, it is often necessary to manage the flow of the reactive resin compound in continuous fashion and/or to keep this flow under a defined pressure. This is particularly true when the reactive resin compound is introduced into a closed form immediately after mixing the two initial components and is hardened or gelled under pressure. This also applies when the flow-through mixer of such a resin preparation system is coupled to a multiple metering apparatus since a material buffer under a defined pressure is necessary for the exact function of the metering means. Special problems arise in the employment of highly reactive resin compounds having a handling time of less than one hour and/or when using rapidly sedimenting, filled reaction resin compounds. It is thereby necessary to keep the dwell time of the reaction resin compounds in the system extremely short and to avoid the sedimentation of reaction resin compound and/or filler.
For the compensation of the pulsation and in order to keep the pressure constant in the automatic preparation of reactive resin compounds, German AS No. 27 46 050 discloses that the static or the dynamic flow-through mixer be followed by what is referred to as a repressing apparatus. The employment of such a repressing apparatus comprising a cylinder and movable piston, however, leads to a longer dwell time of the reaction resin compound in the pipe conduits or to an additional pressure loss in the compound flow. Particularly given highly reactive compounds, a hardening resin layer quickly forms at the walls, this resulting in corresponding constrictions of the cross-section. In addition to frequent interruptions in operation, the elimination of such cross-sectional constrictions requires a high expenditure for maintenance and cleaning.